Steve's Post on the subject can be found here:-
viewtopic.php?t=11841
Recipe
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Hopeful TEA Clone OG 0.1044 20L
4500g Maris Otter Pale Malt
375g Crystal
Goldings 18IBU's (90)
Fuggles 18 IBU's (90)
Golding Aroma/steep 20g
2 Sachets Danstar Nottingham yeast
Method
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Stir grist in 15L liqor @ 72c for a 66c Mash for 90 mins.
[/url]After 90 mins I added 5L of sparge water (90c) to the mashtun, strirred it in, waited, re-circulated a few jug fulls then collected 10 Litres of Wort. This was roughly calculated to be 1.078 meaning in Steve's Instructions I had collected 780 sugarpoints.
After it stopped draining the water was now 83c and I added a further 8L to the mashtun, stirred, waited, recirculated & drained off a further 12L of wort. I had calculated now with a run off of 8 litres @ 1.048 a further 348 sugar points (More than enough).
I used beersmith to convert the hydrometer reading (yes i will get a refractometer) above. Not sure how accurate this is at 60c? However hopefully as you can see the reading was 1.032 (trust me it was) and therefore I avoided my sparge woes of going below 1.008. Hopefully although I added a kilo to my recipe to get an inefficient brew going. The reward will be less tannins in the finished brew.
Collected 18Litres, added liqur to the boiler and fired up.
Its boiling away now - will get you an update later.
edited to insert this update
4.30pm just pitched two sachets of Danstar nottingham at OG 1.044. I diluted to get it down to 1.044 with some liqor (prepared water by boiling off some chalk and adding half a camden tablet.) I think therefore my 36IBU will be nearer 32. This is perhaps where I should have run off the specific amount of the second wort at 1.048 to give me the sugar points i needed. In reality I grabbed more than I needed when I was not sure how much to trust beer smiths hydrometer conversion (better to have too much - I thought). Steve was evidently right when he said a refractometer will be the best £18 I'll ever spend! It's definetely on my list!
I'm pleased you're giving the batch sparge a try. Initially there is a temptation to run off more than you need and you end up either diluting it, or stopping the boil short at the right OG and chucking some away. I always aim for a highish post boil volume at the OG I want after 90 mins boil in order to rule out losses to hops reducing the volume in the FV below what I want, also, it makes for a quicker run off as I don't have to wait for the last dribble to get to the right volume. Also topping up is not necessary. You've hit the main problem with dilution on the head - IBU dilution, though if you didn't add too much liquor I doubt you'd notice it.
A refractometer does make it very easy - you can almost instantly find out what you have at any point in time and you can also take instant readings of boiling wort, and so switch off as soon as you hit your target (a couple of degrees below desired OG). If you tried that with a hydrometer, you might get into an awful mess, probably burn yourself, and be so far behind by the time you could take a reading that the OG would probably have overshot.